Synthesis and antibacterial evaluation of New N-acylhydrazone derivatives from dehydroabietic acid

Synthesis and Characterization of New N-acyl Hydrazone Derivatives of Carprofen as Potential Tuberculostatic Agents

N-acyl hydrazone (NAH) is recognized as a promising framework in drug design due to its versatility, straightforward synthesis, and attractive range of biological activities, including antimicrobial, antitumoral, analgesic, and anti-inflammatory properties. In the global context of increasing resistance of pathogenic bacteria to antibiotics, NAHs represent potential solutions for developing improved treatment alternatives. Therefore, this research introduces six novel derivatives of (EZ)-N'-benzylidene-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide, synthesized using a microwave-assisted method. In more detail, we joined two pharmacophore fragments in a single molecule, represented by an NSAID-type carprofen structure and a hydrazone-type structure, obtaining a new series of NSAID-N-acyl hydrazone derivatives that were further characterized spectrally using FT-IR, NMR, and HRMS investigations. Additionally, the substances were assessed for their tuberculostatic activity by examining their impact on four strains of M. tuberculosis, including two susceptible to rifampicin (RIF) and isoniazid (INH), one susceptible to RIF and resistant to INH, and one resistant to both RIF and INH. The results of our research highlight the potential of the prepared compounds in fighting against antibiotic-resistant M. tuberculosis strains.

Synthesis and crystal structures of (E)-N'-(4-chloro-3-nitro-benzyl-idene)acetohydrazide and (E)-2-(4-chloro-benzyl-idene)-1-(quinolin-8-yl)hydrazine

The syntheses of two benzyl-idenehydrazine derivatives, namely, (E)-N'-(4-chloro-3-nitro-benzyl-idene)acetohydrazide, C9H8ClN3O3, and (E)-2-(4-chloro-benzyl-idene)-1-(quinolin-8-yl)hydrazine, C16H12ClN3, are reported. The mol-ecules have been characterized using IR, 1H NMR, 13C NMR and mass spectro-scopic and elemental analysis techniques, and their structures have been determined by single-crystal X-ray diffraction.

Hydrazone modification of non-food natural product sclareolide as potential agents for plant disease

Plant diseases and their drug resistance pose a serious threat to agricultural production. One way to solve this problem is to discover new and efficient botanical pesticides. Herein, a series of novel hydrazide-hydrazone-containing sesquiterpenoid derivatives were synthesized by simply modifying the structure of the non-food natural product sclareolide. The biological activity results illustrated that compared to ningnanmycin (39.2 μg/mL), compound Z28 had the highest antiviral activity against tobacco mosaic virus (TMV), and the concentration for 50% of maximal effect (EC₅₀) of its inactivation activity was 38.7 μg/mL, followed by compound Z14 (40.6 μg/mL). Transmission electron microscopy (TEM) demonstrated that TMVs treated with compounds Z14 and Z28 were broken into rods of different lengths, and their external morphology was fragmented or even severely fragmented. Autodocking and molecular dynamics (MD) simulations indicated that compound Z28 had a strong affinity for tobacco mosaic virus coat protein (TMV-CP), with a higher binding energy of -8.25 kcal/mol compared to ningnanmycin (-6.79 kcal/mol). The preliminary mechanism revealed that compound Z28 can achieve an antiviral effect by targeting TMV-CP, rendering TMV unable to self-assemble and replicate, and might be a candidate for a novel plant antiviral agent. Furthermore, the curative and protective activities of compound Z22 (EC₅₀ = 16.1 μg/mL) against rice bacterial blight were 51.3% and 50.8%, respectively. Its control effect was better than that of bismerthiazol (BT) and thiadiazole copper (TC), compound Z22 that can be optimized as an active molecule.

Synthesis, characterization, DFT, antioxidant, antibacterial, pharmacokinetics and inhibition of SARS-CoV-2 main protease of some heterocyclic hydrazones

Three hydrazone derivatives have been synthesized using condensation reaction of 4-hydrazinylbenzoic acid with three aromatic aldehydes namely: thiophene-2-carbaldehyde, thiophene-3-carbaldehyde and 2-furaldehyde in ethanol at 78 °C reflux. The synthesized molecules have been characterized using spectroscopic and physicochemical methods including UV-Vis, IR, ¹H NMR, ¹³C NMR, ¹⁵N NMR and melting point determination. Optimized molecular structures, UV-Vis and IR spectra modeling, the reactivity, the stability and some quantum chemical parameters of the synthesized molecules were modeled utilizing density functional theory (DFT). The obtained theoretical results were found in good agreement with the experimental results. On the other hand, the antioxidant and antibacterial activities of the molecules under study were evaluated to better understand the associated mechanisms of action specifically. Also, predicted ADME-T and pharmacokinetic parameters indicated that these compounds showed good oral bioavailability. Finally, molecular docking has been used to predict the inhibitory activity of the studied hydrazone derivatives on the SARS-CoV-2 main protease (Mpro).

A study of antituberculosis activities and crystal structures of (E)-2-[2-(arylidene)hydrazinyl]pyrimidine and (E)-N 1-(arylidene)pyrimidine-2-carbohydrazide derivatives

A study of the anti-tuberculosis activity against Mycobacterium tuberculosis ATTC 27294 and an X-ray structural determination of (E)-2-[2-(arylidene)hydrazinyl]pyrimidine, 1, and (E)-N 1-(arylidene)pyrimidine-2-carbohydazide, 2, derivatives are presented. The effect of the substituents in the aryl moiety on the antituberculosis (anti-TB) activities of 1 and 2 is compared with that of other heteroaryl hydrazonyl and acylhydrazonyl derivatives. The biological activities of 1 do not depend on the coordinating ability of the substituted aryl group: in 2, the most effective aryl group is 5-nitrofuranyl. The structure determinations of (E)-2-((2-(pyrimidin-2-yl)hydrazono)methyl)-phenol, (E)-N′-(2,5-dihydroxybenzylidene)pyrimidine-2-carbohydrazide and of the hydrate of (E)-N′-(2-hydroxy-4-methylbenzylidene)pyrimidine-2-carbohydrazide, and a literature search of related structures in the CCDC data base, allowed an examination of the more important interactions, including the occurrence of X–Y⋯π interactions.

Biocompatibility and mechanical properties evaluation of chitosan films containing an N-acylhydrazonic derivative

The N-acylhydrazone subunit is considered a privileged structure in medicinal chemistry for its importance in pharmaceutical research. Also, alternative methods to deliver these molecules have a great pharmaceutical interest. Therefore, the objective of this work was to encapsulate JR19, an N-acyl hydrazone subunit, into chitosan films and evaluate several properties relevant for transdermal delivery, including biocompatibility using in vitro tests. CHI + JR19 film demonstrates greater strength, flexibility, water absorption capacity, low contact angle and higher surface roughness when compared to CHI. Agar diffusion and 3-(4,5-dimethyl)-2,5-diphenyl tetrazolium bromide (MTT) assay show the absence of cytotoxicity and the higher cell viability for CHI + JR19 films. Therefore, the addition of JR19 in the system positively influenced mechanical properties and granted better compatibility with biological environments, showing the potential to treat skin inflammation.

Synthesis, Characterization and Bioassay of Novel Substituted 1-(3-(1,3-Thiazol-2-yl)phenyl)-5-oxopyrrolidines

Thiazole derivatives attract the attention of scientists both in the field of organic synthesis and bioactivity research due to their high biological activity. In the present study, thiazole ring was obtained by the interaction of 1-(4-(bromoacetyl)phenyl)-5-oxopyrrolidine-3-carboxylic acid with thiocarbamide or benzenecarbothioamide, as well as tioureido acid. A series of substituted 1-(3-(1,3-thiazol-2-yl)phenyl)-5-oxopyrrolidines with pyrrolidinone, thiazole, pyrrole, 1,2,4-triazole, oxadiazole and benzimidazole heterocyclic fragments were synthesized and their antibacterial properties were evaluated against Gram-positive strains of Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes and Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica enteritidis. The vast majority of compounds exhibited between twofold and 16-fold increased antibacterial effect against the test-cultures when compared with Oxytetracycline.

Crystal structures and Hirshfeld surface analyses of a des-A-B-aromatic steroidal compound, and two of its derivatives, having a trans-2,3,4,5-tetrahydro-3a-methyl-7-methoxybenz[e]indane skeleton – structural comparisons with reported tetrahydrobenz[e]indene derivatives

The crystal structures and Hirshfeld surface analyses of the des-A-B-aromatic steroid derivative, (3a,9b)-1,2,3a,4,5,9b-hexahydro-7-methoxy-3a-methyl-3H-benz[e]-inden-3-one (or 5-methoxy-des-A-estra-5,7,9-triene-17-one) 1, its acetohydrazide derivative, 2, and its hydrazone derivative, 3, are reported. All three compounds crystallize in chiral space groups: compounds 1 and 2 in the orthorhombic space group P212121 each with one molecule in the asymmetric unit, and compound 3 in the monoclinic space group P21 with two similar but independent molecules, Mol A and Mol B, in the asymmetric unit. Both the five-membered and six-membered non-aromatic rings in all three compounds have envelope or near envelope shapes. In compounds 2 and 3 the N=N units have (E)-arrangements. The intermolecular interactions in crystals of compound 1 are C–H · · · O hydrogen bonds and C–H · · · π interactions, in compound 2 N–H · · · O and C–H · · · O hydrogen bonds and C–H · · · π interactions are present, while in compound 3 there are just C–H · · · π interactions. An important substructure in 1 is a sheet of molecules, composed of R 6 6 ( 44 ) ${\rm{R}}_6^6(44)$ rings, formed from C–H · · · O(methoxy) and C–H · · · O(carbonyl) hydrogen bonds, the molecules of which form columns linked via the B and D rings, i.e. in a head-to-tail fashion. Compound 2 is an acylhydrazonyl compound, in which the two independent molecules are linked into asymmetric dimers via strong classical N–H · · · O hydrogen bonds, with the formation of R 2 2 ( 8 ) ${\rm{R}}_2^2(8)$ rings. In both 1 and 2, further intermolecular interactions result in 3-dimensional structures, while compound 3 has a 1-dimensional structure arising from C–H · · · O interactions generating spiral chains. The results have been compared with existing data.

Lanthanide–EDTA complexes covalently bonded on Fe3O4@SiO2 magnetic nanoparticles promote the green, stereoselective synthesis of N-acylhydrazones

Highly efficient stereoselective synthesis of E–N-acylhydrazones using magnetic nanoparticles-Ln³⁺ as heterogeneous catalysts.

Crystal structure and Hirshfeld surface analysis of (E)-N'-[4-(piperidin-1-yl)benzyl-idene]aryl-sulfono-hydrazides

The crystal structures and Hirshfeld surface analyses of three Schiff bases, namely (E)-N'-[4-(piperidin-1-yl)benzyl-idene]benzene-sulfono-hydrazide, C18H21N3O2S, (I), (E)-4-methyl-N'-[4-(piperidin-1-yl)benzyl-idene]benzene-sulfono-hydrazide, C19H23N3O2S, (II), and (E)-4-chloro-N'-[4-(piperidin-1-yl)benzyl-idene]benzene-sulfono-hydrazide, C18H20ClN3O2S, (III), derived from aryl-sulfono-hydrazides and 4-(piperidin-4-yl)benzaldehyde have been analysed to investigate the effect of substituents on the structural parameters. All three structures crystallize in monoclinic crystal systems, in the space groups P21/c for (I) and (II), and C2/c for (III). Compound (III) contains two independent mol-ecules in the asymmetric unit and sixteen mol-ecules per unit cell, while (I) and (II) both have one and four mol-ecules, respectively, in their asymmetric units and unit cells. In all cases, the central part of the mol-ecule is twisted at the S atom. In the crystals, the mol-ecules are linked via N-H⋯O hydrogen bonds, forming chains. Two-dimensional fingerprint plots of various inter-atomic contacts show that the major contributions are from H⋯H inter-actions.

Synthesis and Antibacterial Activity of C-7 Acylhydrazone Derivatives of Dehydroabietic Acid

Seven new C-7 acylhydrazone derivatives of dehydroabietic acid were synthesised from dehydroabietic acid through benzylic oxidation, condensation with hydrazine hydrate, followed by nucleophilic substitution reactions with a variety of substituted aromatic acids. The structures of the synthesised compounds were characterised by IR, 1H NMR and MS. The antibacterial activities of the synthesised compounds were evaluated by the disk diffusion method. Antibacterial activity studies showed that C-7 acylhydrazone derivatives of dehydroabietic acid exhibited inhibitory activities against Escherichia coli, Staphylococcus aureus and Bacillus subtilis. Among the seven compounds, dehydroabietic acid p-fluorobenzoyl hydrazone showed the strongest inhibitory activity against B. subtilis and S. aureus.

Effect of antiprotozoal molecules on hypnospores of Perkinsus spp. parasite

Perkinsus protozoan parasites have been associated with high mortality of bivalves worldwide, including Brazil. The use of antiproliferative drugs to treat the Perkinsosis is an unusual prophylactic strategy. However, because of their environment impact it could be used to control parasite proliferation in closed system, such as hatchery. This study evaluated the anti-Perkinsus activity potential of synthesized and commercial compounds. Viability of hypnospores of Perkinsus spp. was assessed in vitro. Cells were incubated with three 2-amino-thiophene (6AMD, 6CN, 5CN) and one acylhydrazone derivatives (AMZ-DCL), at the concentrations of 31.25; 62.5; 125; 250 and 500 μM and one commercial chlorinated phenoxy phenol derivative, triclosan (2, 5, 10 and 20 μM), for 24-48 h. Two synthetic molecules (6CN and AMZ-DCL) caused a significant decline (38 and 39%, respectively) in hypnospores viability, at the highest concentration (500 μM), after 48 h. Triclosan was the most cytotoxic compound, causing 100% of mortality at 20 μM after 24 h and at 10 μM after 48 h. Cytotoxic effects of the compounds 6CN, AMZ-DCL, and triclosan were investigated by measuring parasite's zoosporulation, morphological changes and metabolic activities (esterase activity, production of reactive oxygen species and lipid content). Results showed that zoosporulation occurred in few cell. Triclosan caused changes in the morphology of hypnospores. The 6CN and AMZ-DCL did not alter the metabolic activities studied whilst Triclosan significantly increased the production of reactive oxygen species and changed the amount and distribution of lipids in the hypnospores. These results suggest that three compounds had potential to be used as antiprotozoal drugs, although further investigation of their mechanism of action must be enlightened.

Synthesis, X-ray diffraction study and pharmacological evaluation of 3-amino-4-methylthiophene-2-acylcarbohydrazones

N-acylhydrazone is an interesting privileged structure that has been used in the molecular design of a myriad of bioactive compounds. In order to identify new antinociceptive drug candidates, we described herein the design, synthesis, X-ray diffraction study and the pharmacological evaluation of a series of 3-amino-4-methylthiophene-2-acylcarbohydrazone derivatives (8a-t). Compounds were prepared in good overall yields through divergent synthesis from a common key intermediate and were characterized by classical spectroscopy methods. X-ray diffraction study was employed for unequivocal determination of the imine double bond stereochemistry. 8a-t were evaluated in vivo through oral administration using the classical writhing test in mice. N-acylhydrazone derivatives 8j and 8l displayed relative potency similar to dipyrone, highlighting them as promising analgesic lead-candidates for further investigation.

Synthesis, Structure, Chemical Stability, and In Vitro Cytotoxic Properties of Novel Quinoline-3-Carbaldehyde Hydrazones Bearing a 1,2,4-Triazole or Benzotriazole Moiety

A small library of novel quinoline-3-carbaldehyde hydrazones (Series 1), acylhydrazones (Series 2), and arylsulfonylhydrazones (Series 3) bearing either a 1,2,4-triazole or benzotriazole ring at position 2 was prepared, characterized by elemental analyses and IR, NMR, and MS spectra, and then subjected to in vitro cytotoxicity studies on three human tumor cell lines: DAN-G, LCLC-103H, and SISO. In general, compounds 4, 6, and 8 substituted with a 1,2,4-triazole ring proved to be inactive, whereas the benzotriazole-containing quinolines 5, 7, and 9 elicited pronounced cancer cell growth inhibitory effects with IC50 values in the range of 1.23⁻7.39 µM. The most potent 2-(1H-benzotriazol-1-yl)-3-[2-(pyridin-2-yl)hydrazonomethyl]quinoline (5e) showed a cytostatic effect on the cancer cell lines, whereas N′-[(2-(1H-benzotriazol-1-yl)quinolin-3-yl)methylene]-benzohydrazide (7a) and N′-[(2-1H-benzotriazol-1-yl)quinolin-3-yl)methylene]-naphthalene-2-sulfonohydrazide (9h) exhibited selective activity against the pancreas cancer DAN-G and cervical cancer SISO cell lines. Based on the determined IC50 values, the compound 5e seems to be leading compound for further development as anticancer agent.

Crystal structures of three ortho-substituted N-acyl-hydrazone derivatives

To explore the effect of the nature of substitutions on the structural parameters and hydrogen-bond inter-actions in N-acyl-hydrazone derivatives, the crystal structures of three ortho-substituted N-acyl-hydrazone derivatives, namely (E)-N-{2-[2-(2-chloro-benzyl-idene)hydrazin-yl]-2-oxoeth-yl}-4-methyl-benzene-sulfon-amide, C16H16ClN3O3S (I), (E)-N-{2-[2-(2-methyl-benzyl-idene)hydrazin-yl]-2-oxoeth-yl}-4-methyl-benzene-sulfonamide, C17H19N3O3S (II), and (E)-N-{2-[2-(2-nitro-benzyl-idene)hydrazin-yl]-2-oxoeth-yl}-4-methyl-benzene-sulfonamide, C16H16N4O5S (III), have been determined. The structures of the three compounds display similar mol-ecular conformations and hydrogen-bond patterns. The hydrazone part of the mol-ecule, C-C-N-N=C, is almost planar in all the compounds, with the C-C-N-N and C-N-N=C torsion angles being 179.5 (3) and 177.1 (3)°, respectively, in (I), -179.4 (2) and -177.1 (3)° in (II) and -179.7 (2) and 173.4 (2)° in (III). The two phenyl rings on either side of the chain are approximately parallel to each other. In the crystal, the mol-ecules are linked to each other via N-H⋯O hydrogen bonds, forming ribbons with R22(8) and R22(10) ring motifs. The introduction of electron-withdrawing groups (by a chloro or nitro group) to produce compounds (I) or (III) results in C-H⋯O hydrogen-bonding inter-actions involving the sulfonyl O atoms of adjacent ribbons, forming layers parallel to the ab plane in (I) or a three-dimensional network in (III). In (III), one O atom of the nitro group is disordered over two orientations with refined occupancy ratio of 0.836 (12):0.164 (12).

Identification of a diverse synthetic abietane diterpenoid library and insight into the structure-activity relationships for antibacterial activity

A diverse natural product-like (NPL) synthetic abietane diterpenoid library containing 86 compounds were obtained and the SARs were studied based on their antibacterial potential. Further in vitro cytotoxic and in silico drug-like properties evaluation showed that the potent antibacterial compound 84 had good drug-like properties and displayed low cytotoxicity toward noncancerous mammalian cells, indicating the study of AA and DHAA might be a good starting point for the search of novel antimicrobial molecules. Future work should be focused on the optimization of their potency and selectivity.

The synthesis and antistaphylococcal activity of dehydroabietic acid derivatives: modifications at C12 and C7

A series of 7-N-acylaminoethyl/propyloxime derivatives of dehydroabietic acid were synthesized and investigated for their antibacterial activity against Staphylococcus aureus Newman strain and multidrug-resistant strains (NRS-1, NRS-70, NRS-100, NRS-108 and NRS-271). Most of the target compounds having trifluoromethyl phenyl/benzyl, halogen-substituted thiophenyl, benzothiophenyl or pyrrolyl moiety exhibited potent in vitro antibacterial activity. Among which, compounds 4m, 4x and 7j showed high antibacterial activity with minimum inhibitory concentration (MIC) values of 1.25-3.13 μg/mL against five multidrug-resistant S. aureus.

Efficient access to novel androsteno-17-(1',3',4')-oxadiazoles and 17β-(1',3',4')-thiadiazoles via N-substituted hydrazone and N,N'-disubstituted hydrazine intermediates, and their pharmacological evaluation in vitro

A series of novel 17-exo-oxadiazoles and -thiadiazoles in the Δ(5) androstene series were efficiently synthesized from pregnenolone acetate and pregnadienolone acetate via multistep pathways. 17β-(1',3',4')-Oxadiazoles were obtained in high yields by the phenyliodonium diacetate-induced oxidative ring closure of semicarbazone and N-acylhydrazones derived from 3β-acetoxy- and 3β-hydroxyandrost-5-ene-17β-carbaldehydes. For the synthesis of analogous Δ(16)-17-oxadiazolyl derivatives, N,N'-disubstituted hydrazine intermediates were prepared from 3β-acetoxyandrosta-5,16-diene-17-carboxylic acid, which then underwent cyclodehydration in the presence of POCl3. The cyclization of steroidal N,N'-diacylhydrazines containing a saturated ring D with the Lawesson reagent afforded 17β-(1',3',4')-thiadiazoles in good yields. Most of the products were subjected to deacetylation in basic media in order to enlarge the compound library available for pharmacological studies. All of these derivatives were screened in vitro for their antiproliferative effects against four malignant human adherent cell lines (HeLa, A2780, MCF7 and A431) by means of the MTT assay. The 3β-hydroxy derivatives of the newly-synthesized 17-exo-heterocycles were tested in vitro to investigate their inhibitory effects on rat testicular C17,20-lyase. One of the 1,3,4-oxadiazolyl derivatives proved to exert noteworthy enzyme-inhibitory action, with an IC50 (0.065 μM) of the same order of magnitude as that of abiraterone.

Synthetic derivatives of aromatic abietane diterpenoids and their biological activities

Naturally occurring aromatic abietane diterpenoids (dehydroabietanes) exhibit a wide range of biological activities. A number of synthetic studies aimed at modifying the abietane skeleton in order to obtain new potential chemotherapeutic agents have been reported. In this study, the biological activities of synthetic derivatives of aromatic abietane diterpenoids are reviewed.

Dehydroabietic acid derivative QC2 induces oncosis in hepatocellular carcinoma cells

Aim. Rosin, the traditional Chinese medicine, is reported to be able to inhibit skin cancer cell lines. In this report, we investigate the inhibitory effect against HCC cells of QC2, the derivative of rosin's main components dehydroabietic acid. Methods. MTT assay was used to determine the cytotoxicity of QC2. Morphological changes were observed by time-lapse microscopy and transmission electron microscopy and the cytoskeleton changes were observed by laser-scanning confocal microscopy. Cytomembrane integrity and organelles damage were confirmed by detection of the reactive oxygen (ROS), lactate dehydrogenase (LDH), and mitochondrial membrane potential (Δψm). The underlying mechanism was manifested by Western blotting. The oncotic cell death was further confirmed by detection of oncosis related protein calpain. Results. Swelling cell type and destroyed cytoskeleton were observed in QC2-treated HCC cells. Organelle damage was visualized by transmission electron microscopy. The detection of ROS accumulation, increased LDH release, and decreased ATP and Δψm confirmed the cell death. The oncotic related protein calpain was found to increase time-dependently in QC2-treated HCC cells, while its inhibitor PD150606 attenuated the cytotoxicity. Conclusions. Dehydroabietic acid derivative QC2 activated oncosis related protein calpain to induce the damage of cytomembrane and organelles which finally lead to oncosis in HCC cells.

Anti-tuberculosis evaluation and conformational study of N-acylhydrazones containing the thiophene nucleus

A series of N-acylhydrazonyl-thienyl derivatives (compounds 2 and 3), mainly of the type 2-(aryl-CH=N-NHCOCH2 )-thiene (2: aryl = substituted-phenyl; 3: aryl = heteroaryl) were evaluated against Mycobacterium tuberculosis. Particularly active compound was 3 (heteroaryl = 5-nitrothien-2-yl or 5-nitrofuran-2-yl) with MIC values of 8.5 and 9.0 μM, respectively. Moderately active compounds were compound 3 (heteroaryl = pyridin-2-yl) and compound 2 containing aryl = 2- or 4-hydroxyphenyl groups, with MIC values between 170 and 408 μM. Compound 2 containing OMe, H, F, Cl, Br, CN, and NO2 substituents and compound 3 (heteroaryl = furan-2-yl, thien-2-yl, pyrrol-2-yl, imidazol-2-yl, pyridin-3-yl, and pyridin-4-yl) were all inactive. Clearly, there is no correlation of activity with the electronic effects of the substituents. The activities suggest different modes of biological action of the compounds having nitro-heteroaryl groups, on the one hand, and the 2-hydroxyphenyl or pyridin-2-yl substituents, on the other hand. Compounds having 2- or 4-hydroxyphenyl, 2-hydroxy-5-nitrophenyl, or 4-hydroxy-3-chlorophenyl were less cytotoxic than ethambutol. It is important to notice that compound 3 (aryl = 5-NO2 -furan-2-yl) exhibited a promising therapeutic index (TI = 1093.90), with a value 4.4 less than that of ethambutol. Compounds 2 and 3 exist in DMSO or MeOD solutions as mixtures of EC(O)N /EC=N and ZC(O)N /EC=N conformers.

A facile access to novel steroidal 17-2'-(1',3',4')-oxadiazoles, and an evaluation of their cytotoxic activities in vitro

Novel types of 17-exo-heterocycles in the Δ(5) androstene series carrying an 1,3,4-oxadiazole moiety were efficiently synthesized via aldehyde N-acylhydrazone intermediates, obtained from the microwave-assisted condensation of 3β-hydroxy- or 3β-acetoxyandrost-5-ene-17β-carbaldehyde with different acylhydrazides. The subsequent phenyl iodonium diacetate-induced oxidative cyclization proceeded under mild conditions. The synthesized compounds were subjected to in vitro pharmacological studies to investigate their antiproliferative activities on four malignant adherent cell lines (HeLa, MCF7, A2780 and A431), and exhibited the highest potency against HeLa cells, some of them revealing action comparable to that of the reference agent cisplatin.

Synthesis and antibacterial evaluation of some novel imidazole and benzimidazole sulfonamides

Several new substituted sulfonamide compounds were synthesized and their structures were confirmed by ¹H-NMR, ¹³C-NMR, FT-IR, and mass spectroscopy. The antibacterial activities of the synthesized compounds were screened against standard strains of six Gram positive and four Gram negative bacteria using the microbroth dilution assay. Most of the compounds studied showed promising activities against both types of bacteria.